(<i>E</i>)-α-Substituted γ-Alkoxyallylboronic Esters as New Reagents: Synthesis and Reactivity toward Aldehydes

Abstract

We have developed a synthesis of new allylboration reagents based on an allylic rearrangement. This approach led to the α-substituted γ-alkoxyallylboronates 2 with a high stereoselectivity in favor of the E-isomer, independent of the organometallic used. We have also studied the reactivity of these reagents toward aldehydes, showing that the allylboration reaction occurs with an excellent diastereoselectivity to give the anti-diol derivatives 5. Moreover, the sequence can be carried out in a “one-pot” procedure avoiding the purification of allylboronates.